Haber Process Flashcards
What do most fertilisers contain?
Nitrogen
What forms ammonia?
nitrogen + hydrogen
What conditions are used?
200 atmospheres 450C and an iron catalyst
What do you do with any unreacted hydrogen and nitrogen?
Recycle them
What are nitrogen based fertilisers used for?
Making proteins
What do plants take up?
soluble nitrate ions NO3-(aq)
What happens when you harvest crops?
nitrogen is removed
Why is ammonia important? (3 reasons)
- 78% of nitrogen is in atmosphere
- Nitrogen gas is insoluble in water
- Plants need soluble form
- ’Fixing’ nitrogen
What is meant by ‘fixing’ nitrogen?
When gaseous nitrogen is turned into nitrogen compounds that can be absorbed in solution by plants
Raw materials for the production of ammonia?
Nitrogen (from air)
Hydrogen (mainly from natural gas)
What’s the symbol for ammonia?
NH3
Flow diagram (5 steps)
- Nitrogen and hydrogen pumped through pipes
- Pressure is increased to 200 atmospheres
- Pressurised gases are heated to 450°C and passed through tank with iron catalyst
- Mixture is cooled so that ammonia liquifies and is removed
- Unreacted nitrogen and hydrogen are recycled. They are re-compressed and heated before returning to reaction vessel
What’s the word equation for ammonia?
nitrogen + hydrogen <> ammonia
What’s the symbol equation for ammonia?
N2(g) + 3H2(g) <> 2NH3(g)
What is yield?
the amount of product made compared to amount we would make is all reactants were used
